USS Pampanito SS-383, a Balao class (1943 built) submarine memorial
and museum in San Francisco, CA is in a unique position to restore and
preserve its original Arma Corporation Mark VII gyrocompass ("gyro") navigation
equipment. This gyro is now the only working example of this technology in
the United States. There was a narrow window of opportunity to complete
the restoration. The few remaining experts with the necessary knowledge
are near retirement and the last shop equipped for this restoration is
no longer used, it was held intact for a couple of years just for
this project. During the restoration the knowledge of how to maintain
this technology has been recorded before it was lost. Pampanito's
crew gathered the needed parts and equipment, identified the key
personnel
and secured the cooperation of the shop; the project is nearly complete.

The Maritime Park Association operates Pampanito's preservation program
with the goal of making Pampanito as complete and as accurate as possible,
striving for a summer 1945 configuration. To date we have restored over
50% of her systems to working order including four of her five diesel engines,
main hydraulics, high pressure air, most of the radio gear, torpedo
data computer,
and cipher systems. We work very closely with the US Navy as well as private
sources to acquire the equipment missing from the boat.

The restoration of the gyro is of special importance to the Pampanito's
mission in several ways. During the restoration, the apprenticed art of
"setting up" (balancing) an Arma sensitive element has been fully documented
for the first time, missing components have been replaced and damaged wiring
repaired. Now that the completeness of the system has been verified
through operation
the system, it is being preserved with basic maintenance. Its preservation
will enable the future study of not only the gyro, but also the surprisingly
sophisticated WW II fire control system. The gyrocompass is used to
interpret navigation technology, basic principles of physics, basic principles
of navigation and fire control during educational programs. We serve over
200,000 visitors a year including several thousand children in overnight
programs.

Time was a critical factor. The most pressing concern was the availability
of craftsman capable of performing the specialized shop work.
Virtually all the experts
have retired and were no longer capable of performing the 200+ hour job.
The second source of urgency was the availability of a properly equipped
shop. The last shop equipped to perform the work in the United States has
had not used its Arma Mk VII shop gear for many years (1972). It retained
this valuable shop space intact only for this project for a couple of years
while we prepared. The shop's Arma experienced staff were all near
retirement age.

Pampanito is perhaps the best example of the peak of WW II submarine
technology to survive. Pampanito was refit with the latest submarine fire
control and navigation technology just before the end of the war and has
received no significant post WW II upgrades or modifications. Her
Torpedo Data Computer
(the second most important part of the fire control system) is in the original
WW II configuration and has been restored (the only Mk III TDC
operational in the world) to operation (this includes its inputs from
the gyro.) We have assembled all
the other major components necessary to complete the original WW II fire
control system. We believe this system has historical importance and needs
to be preserved.

NARRATIVE:

The gyrocompass is the most important high technology equipment aboard
a submarine. Without the gyro, navigation below the seas for attack or
escape is difficult and fire control systems are cumbersome. The gyro is
an integral part of the fire control system that includes the torpedo data
computer, dead reckoning analyzer, dead reckoning tracers, dummy log, pit
log, sonars, and radars. This highly integrated system was years ahead
of competitive systems and was one of the crowning achievements of WW II
technology. The Arma gyro technology aboard Pampanito is particularly
interesting.

During the 1930s two companies, Arma and Sperry, created competitive gyro
technologies. During WW II all US submarines had Arma main gyros identical
to those on Pampanito. Surface ships used either type of equipment, but
more Sperry equipment was installed. It is interesting that the very largest
ships, aircraft carriers, battleships and cruisers received mostly Arma
gyrocompasses. During the post-war period Sperry was more successful as
a company and as a result fewer Arma gyros survive today.

We located the last Arma gyro repair shop in the United States: Gyro Systems Inc. in Virginia
Beach, VA. As Arma gyros
became more and more obsolete the market for their repair and maintenance
diminished. Fewer and fewer gyro repair shops stayed in the business and
Gyro Systems Inc. slowly acquired their stocks and the few remaining customers.
The last of these gyros is long gone and we were fortunate to contact Gyro
Systems Inc. as they were preparing to dispose of the last of this long
obsolete equipment. They have very generously donated all the
spare parts and equipment we have used. Further, they still have all the shop
tools, gauges, equipment, etc. needed to setup an Arma gyrocompass sensitive
element (including the delicate rotor mechanisms). They provided the
use of these
facilities for free before they are dismantled. We were hoping to get a
72-year old former Navy expert on gyros to perform the 200+ hour job of
setting up the sensitive element. Unfortunately health problems made
this impossible. When we could not get the skilled labor for free, Gyro
Systems president, Buddy Creakmore generously donated the skilled
labor. These are the most qualified people available
to perform this work and quite probably the only ones not yet
retired.

The existing Arma documentation barely captures the process
of setting up the sensitive element to a level that would allow repetition
after the current generation of experts are gone. Servicing any mechanical
gyrocompass has always been more an art than a science. The reason is that
the forces at play to make the compass work are very small and are dependent
on a delicate balance of all components to be expressed accurately. This
was an apprenticed skill that was never completely captured in writing.
Among those servicing these gyros, craftsman of greater skill were known
an respected among their peers. Gyro Systems Inc. has two such men
still working
who are skilled in the servicing of the Arma gyros and all the specialized
shop equipment. When they retire, this art would have been lost. We
were able to restore this system and document the sensitive
element setup by last skilled craftsmen available.

We understand that the operation of most types of equipment is a necessary
component of a long term preservation plan for many reasons. First, idle
equipment frequently deteriorates faster than operating equipment. The
operation distributes lubrication, dries components, discovers incremental
problems in their nascent stages, and avoids material creep. Second, although
Pampanito has had no post WW II additions, modifications and removals did
occur during the 1960s and 1970s when she was used as reserve trainer and
then opened for stripping by other Navy units. As a result, wiring was
modified and parts were removed from many systems on the boat. No system
can be assured complete and accurately assembled until it has been operated
at least once. Third, our experience has shown that many safety problems
are found and corrected during the restoration of equipment to operational
status. Fourth, in restoring equipment to operation, the skills of repair
and operation are themselves preserved in a way not possible with static
displays. Finally, operating equipment inspires respect and care not offered
inoperable equipment. This is true not only of its caretakers, but also
those that might be inspired by it. There is a magic to teaching with a
complete and operable system that is not possible with equipment of unknown
condition. Of course, when long term operation is not sustainable, equipment
is brought to operable state and then properly laid up.

GOALS OF THE PROJECT:

Restore Pampanito's main gyrocompass to operable condition. Operate
it on an scheduled basis as needed for preservation. Create a gyrocompass
binnacle emulation device for system testing and demonstration of the system.
Implement a plan for long term preservation. Implement a plan of education
and interpretation.

Priority

Goal

Nearly Completed, final balance is not
completed. One rotor has a slow leak.

Restore the gyrocompass binnacle. This consist
primarily of balancing the sensitive element. Repair the spider and follow-up
mechanisms.

Underway. All except follow up amplifier
are fully working.
Follow up amp is working, but not to specification.

Restore main control panel.

Completed

Restore and install replacement gyro motor
generators.

Completed. All except forward torpedo room.

Restore gyro repeaters and its cabling.

Completed

Create a Own Ships Course emulation device to
drive an Arma repeater. This is used to test individual repeaters, and
to supply a simulated signal for emulating the
function of the gyro itself. This allows running simulated attacks
testing the rest of the fire control system including TDC. It may also
be used during interpretive programs.

Ongoing

Document all work. Especially the art of setting
up the sensitive element of the gyro. Capture detailed photographs of all
process steps, video of particularly dynamic steps, and textual notes.

High

Visitor proofing for side of Gyro control panel
so it can be powered up with visitors aboard.

Med

Replace the Alarm Flasher (if we can find one).

Completed

The gyro circuits are OK from the TDC to the
control panel. The own course synchros are good in the TDC. A replacement
follow-up amplifier has been installed and wired to the main control
panel.

Completed

Restore high current 120 VAC and 120 VDC to
IC Switchboard. Restore power supply wiring from IC Switchboard to the
main gyro control panel.

Very, very little is needed. Gyro must be spun
up periodically if it is to retain calibration.

Volunteer crew.

A SHORT HISTORY OF THE ARMA GYROCOMPASS:

USS Pampanito is in a unique position to preserve and restore a fine
example of a WW II, Arma Mk 7 Gyrocompass. Outside of the unique technology
of this device, the Arma gyrocompass has a unique place in history.

The practical gyrocompass was invented by the creative genius Elmer
Sperry ca 1904. A gyrocompass measures the movement of a ship around small
wheels turning at high speed to track the movement of a ship. Historically
this invention was more important than the invention of the present day
global positioning system. For the first time in history it was possible
to instantaneously and accurately determine your vessel's location at all
times no matter what forces caused its motion. It worked in all weather,
was less prone to local anomalies, and could be used no matter how much
steel was used to build the ship. When during the 1930s it was extended
to three dimensions it was the basis not only of navigation, but also fire
control.

Elmer Sperry and his company held a monopoly on this critically important
technology through its patents. However, Germany's Aunshutz company created
its own version of the gyrocompass before WW I. Sperry sued Aunshutz in
those pre-WW I years in the international court at the Hague. We have extensive
correspondence between Sperry and his lawyers showing his deep personal
interest in the progress of the case. At the end of WW I the US Navy took
the Aunshutz gyrocompass technology from Germany as a prize of war. The
Navy immediately turned this technology over to the Arma corporation in
an effort to create a competitor to Sperry. Arma improved the Aunshutz
design with its own innovations a produced a gyro. Sperry then sued Arma,
however it was quickly resolved by the US Navy.

The Aunshutz compass had several advantages over the Sperry design,
most importantly the refinement of putting the gyro wheels at an oblique
angle to each other. This approach was inherently more stable than the
orthogonal Sperry arrangement. This allowed creating smaller, more accurate
gyros. The trade off was that in order to read the course it was necessary
to adjust the frequency of the wheels rotation based on the latitude. This
adjustment was simple to implement and with uniquely Arma improvements
a very fine gyrocompass was created.

As part of the arrangement between the US Navy, Arma and Sperry, it
was agreed that Sperry would remain the primary gyrocompass supplier. However,
because of its critical importance to modern warfare, the Navy would insist
on two suppliers. The same was true of the critical fire control equipment
and stable elements.

The Arma equipment was supplied to all submarines for several reasons.
First it was inherently smaller, more stable and required less maintenance.
Second, it was easier to adjust during operation. Third, it had lower power
consumption. Lastly it was easier to start and stop, an important advantage
in a submarine that was trying to evade enemy acoustic detection.

Because Arma was the secondary supplier, fewer Arma gyrocompasses were
made. Of those produced, most were in submarines and few of these have
been preserved.

As the Arma corporation slowly decayed until it ceased to operate in
1976, support for the equipment underwent a consolidation among the third
party vendors. Gyro Systems Inc, a leader in the repair of this technology
slowly acquired the market of customers and inventories of parts and equipment
until it remained as the last remaining repair center for Arma gyros. The
last of these gyros was removed from active service in the late 1980s.